Why summer weather forecasts are inaccurate

In fact, most weather forecasts are accurate, but they are for cities or places, and the area they cover is too large. Although they are in the same city, but in different villages and towns, there will be differences. The weather is not raining where I am, but it is pouring rain a few kilometers away, or even hundreds of meters away. This is especially obvious in summer when showers are the main weather, and in autumn and winter when it is mainly cloudy and rainy days. At this time, the feeling that the weather forecast is inaccurate is very small.